Results of a phase II study suggested that a stimulant drug approved to treat attention deficit-hyperactivity disorder (ADHD) may improve cognitive function in adults with major depression, its manufacturer said.
According to the British firm Shire, patients with partial or full remission of depression symptoms who were on primary antidepressant therapy -- and had residual cognitive impairment -- showed significant improvements in executive function when lisdexamfetamine dimesylate (Vyvanse) was added to their daily treatment.
Lisdexamfetamine dimesylate is currently approved in the U.S. for ADHD in adults and children 6 and older.
Specific results in the 143-patient trial were not disclosed in Shire's announcement, but the company said the drug was significantly superior to placebo in the primary outcome measure, which was mean change in global executive composite scores on the adult Behavioral Rating Inventory of Executive Function. The randomized, placebo-controlled trial ran for nine weeks.
The drug was also superior to placebo in a secondary endpoint, mean change in Montgomery-Asberg Depression Rating Scale scores from baseline to the end of the double-blind treatment phase, Shire said.
A total of 24 patients discontinued treatment during the study, and were almost evenly split between the active drug and placebo. The study drug was administered at 20 mg to 70 mg per day over the first six weeks. The optimal individual dose was continued during a three-week dose maintenance period.
Adverse events led to the discontinuations in four patients assigned to lisdexamfetamine and one taking placebo.
The four events in the active-drug group were loss of consciousness, suicidal ideation, rash, and worsened depression. Trial monitors determined that the loss of consciousness was probably treatment-related whereas the suicidality was not, according to Shire.
Among all treatment-emergent adverse events, those occurring in more than 5% of patients that were more than twice as common with lisdexamfetamine included decreased appetite, insomnia, urinary tract infection, severe sweating, and somnolence.
Hemodynamic effects of the drug were similar to those seen in ADHD patients, the company said.
Shire said it planned to discuss the results with regulatory agencies in determining the next steps for gaining approval of an expanded indication for lisdexamfetamine.